Pneumatically inflatable seals, which come in many different designs, are widely used for effecting a seal between two surfaces. In a typical application one member, for example a door or cover, may be movable between open and closed positions relative to a second member. An inflatable seal, mounted in one of the members, is normally spaced from the other member to accommodate opening and closing but is inflated and expanded after closing in order to close and seal the space between the two members. In one widely used form of pneumatically inflatable seal, sometimes referred to herein as a recessed seal, an elongated elastomeric sealing element is received within a retaining groove provided in one of the members. When deflated, the sealing element typically is wholly contained within the groove. Typically the space between the two members to be sealed is relatively small, and inflation of the sealing element causes it to expand and extend an outer surface portion out of the retaining groove to make contact with the opposite member and form the desired seal.
With known forms of recessed seals, it is customary to provide retention means for retaining the seal in its groove. Such retention means can be provided in the configuration of the groove, for example with retention elements, flanges or the like, or by means of adhesives. Both arrangements have disadvantages. Configuring the groove with retention means involves extra machining, while the use of adhesives involves additional labor. Moreover, for many sealing applications involving recessed seals, periodic cleaning is necessary or desirable, which can be difficult and expensive with conventional forms of recessed seals utilizing conventional retention means. While it has been attempted to utilize seal and groove designs in which the groove is straight sided and the seal is retained by friction with the side walls, the experience has not been satisfactory. The seals, with repeated expansion and deflation cycles over time, tend to “walk” toward the open top of the groove and in time become improperly positioned, resulting in an improper or ineffective sealing and also possibly subjecting the seal to damage during opening and closing of the mechanism to be sealed.